"They bring balance to the ecosystem, and they are part of our history in Pennsylvania and worth preserving," Ryan Miller, a zoologist with the conservancy, said about the snakes.

Miller wouldn't disclose the exact location of the property, only saying it was in the northwestern corner of Venango County. The conservancy said the property contains more than 12 acres of wetlands and 1,600 feet of stream.

"We know (the snakes) are in the area," Miller said. "They're very hard to find, they stay hidden in the grass."

Miller said it's unknown how many of the rattlers live on the Venango County land or in three other sites in Venango and Butler counties, but the numbers have been dwindling.

"One place is just a 2-acre area of grass," Miller said. "They are barely hanging on."

He added that the conservancy has tagged about 300 of the rattlers statewide with microchips, so they can be tracked. Miller said poaching is a concern, and law enforcement will be able to track the snakes with the microchips. He said some people believe that snake venom can help with medical problems, and has been explored for treatment of arthritis, polio and multiple sclerosis.

Miller said the snakes eat mice and rodents, which help balance out the ecosystem.